With the supporters of WikiLeaks having initiated their ‘Operation Payback’ crusade against the companies that have withdrawn services from the contentious whistle-blowing site after its infamous leak of secret cables from US diplomats, there are concerns mounting about the possibility of a cyber war of attacks and counter-attacks.

The hackers involved in the ‘Operation Payback’ are chiefly targeting the websites of global companies that have blocked business with WikiLeaks. The companies whose sites have been crashed by the hackers include those run by the financial groups - MasterCard, Visa and PayPal – as well as some sites of the Swedish government.

With some other sites also having witnessed sporadic outrages, as a result of the Internet activists’ ‘Operation Payback,’ Attorney General Eric Holder said US authorities are looking into the cyber attacks, and are “aware of the incidents.”

That the attacks have drawn the attention of not only the US authorities, but also governments of other countries, is evident from the fact that the Dutch police Thursday arrested a 16-year-old boy, who is suspected to be involved in attacks on credit card sites of Visa and MasterCard.

According to the details shared by the prosecution in the Netherlands on its website, the teenager – whose identity remains undisclosed - was arrested by a high-tech crime unit in The Hague; and is supposedly part of a bigger group of hackers that participated in so-called ‘denial of service’ (DoS) attacks.